The present invention provides a reamer (100) having at least one journal body (110) and at least one toroidal cutter body (116). The toroidal cutter body (116) has a maximum diameter (MD), an outer perimeter (OP) and a plurality of cutting elements (112, 145, 149) on the cutting surface (118). The toroidal cutter body is rotatably attached to the journal (110). When in the installed position, the axis of rotation (RA) of the at least one toroidal cutter body (116) intersects the longitudinal axis of the drill string at an acute angle.
In accordance with the teachings of the present invention, a method is provided for preventing formation of sludge in a subsurface cavity having particulate laden fluid disposed therein. The method includes positioning a downhole device having a fluid agitator into the fluid of the subsurface cavity and agitating the fluid using the fluid agitator.
In accordance with the teachings of the present invention, a method is provided for preventing formation of sludge in a subsurface cavity having particulate laden fluid disposed therein. The method includes positioning a downhole device having a fluid agitator into the fluid of the subsurface cavity and agitating the fluid using the fluid agitator.
